A turbomachine comprises equipment which must be lubricated and/or cooled, such as for example bearing blocks, reducing gears, electric machines and their respective enclosures. For this, the turbomachine comprises a lubrication group feeding an oil circuit in which the oil plays the role of lubricant and heat-exchange fluid. Thermal power transmitted by the equipment to the oil is then discharged by means of heat exchangers of fuel-oil type and/or air-oil type.
The lubrication group comprises especially a pump which is driven by an accessory gearbox, well known to the expert under the name “Accessory Gear Box” (AGB). The AGB is connected via a transmission shaft to a shaft of the turbomachine, generally the high-pressure shaft, to power these different accessories.
Currently, the cooling of equipment is dimensioned to take-off to the extent where it is about the flight phase which generates the most thermal power. For other flight phases the cooling of equipment varies as a function of the speed of rotation of the high-pressure shaft to the extent where it drives the pump of the lubrication group via the AGB.
But it eventuates that, outside the take-off phase, the cooling of different equipment is greater than necessary, which generates substantial thermal losses and pressure losses in exchangers and substantially reduces the yield of the turbomachine. The cooling of equipment is therefore adapted neither to the flight phase of the turbomachine nor to the type of equipment to be cooled.